I want to adopt my wife's son. I married her 12 years ago. The boy is 17 years old now. We do not where the biological father is.

I want to adopt my wife's son. I married her 12 years ago. The boy is 17 years old now. We do not where the biological father is.

Then try to locate him...
If you cannot locate him, you will have to go through court procedure.
FAMILY.CODE
SECTION 8600-8622

8606. Notwithstanding Sections 8604 and 8605, the consent of a
Birth parent is not necessary in the following cases:
(a) Where the birth parent has been judicially deprived of the
Custody and control of the child (1) by a court order declaring the
Child to be free from the custody and control of either or both birth
Parents pursuant to Part 4 (commencing with Section 7800) of
Division 12 of this code, or Section 366.25 or 366.26 of the Welfare
And Institutions Code, or (2) by a similar order of a court of
Another jurisdiction, pursuant to a law of that jurisdiction
Authorizing the order.
(b) Where the birth parent has, in a judicial proceeding in
Another jurisdiction, voluntarily surrendered the right to the
Custody and control of the child pursuant to a law of that
Jurisdiction providing for the surrender.
(c) Where the birth parent has deserted the child without
Provision for identification of the child.
(d) Where the birth parent has relinquished the child for adoption
As provided in Section 8700.
(e) Where the birth parent has relinquished the child for adoption
To a licensed or authorized child-placing agency in another
Jurisdiction pursuant to the law of that jurisdiction.


You have to file for termination of parental rights and adoption.
Pay attention that you have to convince the judge that you made all efforts to locate the father.

Then try to locate him...
If you cannot locate him, you will have to go through court procedure.
FAMILY.CODE
SECTION 8600-8622

8606. Notwithstanding Sections 8604 and 8605, the consent of a
birth parent is not necessary in the following cases:
...

None of the subsections to Section 8622 seem to apply. The closest one is

"(c) Where the birth parent has deserted the child without provision for identification of the child.",
But I don't know that the "without provision for identification" language applies. It looks like that has to do with leaving a foundling on someone's doorstep.

There is probably an appropriate statutory provision for TPR, but I don't think this is it.

The bottom line is you need an attorney to process the adoption petition. So hire yourself an attorney and let them do their job.